This invention relates to the field of ethylene oligomerization.
A variety of catalysts, both homogeneous and heterogeneous, have been disclosed as oligomerization catalysts for ethylene. For example, U.S. Pat. No. 4,482,640 and U.S. Pat. No. 4,487,847 disclose ethylene oligomerization and ethylene dimerization catalysts and processes. Efforts to raise the productivity and selectivity of oligomerization catalysts and processes is ongoing due to the increasing importance of molecules with a molecular weight greater than ethylene.